Organization: University of Rochester - Rochester, New York
Lines: 41
Nntp-Posting-Host: uhura.cc.rochester.edu
In <9301201029.aa18306@Bonnie.ics.uci.edu> xlee@Bonnie.ICS.UCI.EDU (_______________________________________________________________________________) writes:
>What is DCTV?
Quite simply Digital Composite TeleVision. Digital Creations decided
to create a board that could be considered 24-bit. For around $400 retail
this handy little black box is an external device that will achieve 24-bit
color output. Two cables, one plugs into the Amiga's monitor port (has a
pass-through) the other into the parallel port, feed DCTV with signals
encoded into a standard IFF Hi-res 16 colo picture. To a standard RGB
monitor this display doesn't look like much, however, when a composite
monitor is connected to DCTV itself, 16.9 million colors can be displayed on
a 736 by 482 (interlaced) display.
DCTV differs from other 24-bit devices in
that the video signal it generates is not RGB, but rather a composite
output. It is full NTSC composite output and can be viewed by any composite
monitor. This makes using DCTV really convenient for videotaping 24-bit
images or animations.
DCTV creates 24-bit images by real-time manipulation of the Amiga's
standard IFF Hi-res output. DCTV encodes color information in the top and
left borders of the image. DCTV sees this code and presents it as 24-bit
composite video. Because DCTV uses Hi-res screens the amount of memory in a
standard 16.9 million color image is small. In fact only as large as a
standard Hi-res file would be. This ranges from 10k to 150k. Obviously
interlaced images take up the higher end.
24-bit real-time animations can be created as easily as if a Hi-res
animation were being made. This is because DCTV is essentially using the
Amiga's own Chip Ram as a framebuffer.
DCTV's software is very good. It can read pretty much any IFF image
(even 24-bit). It can write three types of files. 24-bit IFF (500k+), Raw (a
form used exclusively by DCTV 200k+), and Display (10k - 150k standard
Hi-res IFF). Raw is primarily used by DCTV for exact reproduction in quality
of image. 98% of the time Display is the best and smallest file format.
If this doesn't make much sense, sorry. I'll summarize.
DCTV takes the Amiga's display and makes it 24-bit composite video
output. That should do it.
Let it not be forgotten that DCTV is also a full 24-bit digitizer as
well. Images need 6-8 secs. to ge grabbed from any composite source. And
